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Title: The Isolated Sixth Gelsolin Repeat and Headpiece Domain of Villin Bundle F-Actin in the Presence of Calcium and Are Linked by a 40-Residue Unstructured Sequence

Abstract

Villin is an F-actin regulating, modular protein with a gelsolin-like core and a distinct C-terminal 'headpiece’ domain. Localized in the microvilli of the absorptive epithelium, villin can bundle F-actin and, at higher calcium concentration, is capable of a gelsolin-like F-actin severing. The headpiece domain can, in isolation, bind F-actin and is crucial for F-actin bundling by villin. While the three-dimensional structure of the isolated headpiece is known, its conformation in the context of attachment to the villin core remains unexplored. Furthermore, the dynamics of the linkage of headpiece to the core has not been determined. To address these issues, we employ a 208 residue modular fragment of villin, D6-HP, which consists of the sixth gelsolin-like domain of villin (D6) and the headpiece (HP). We demonstrate that this protein fragment requires calcium for structural stability and, surprisingly, is capable of Ca2+-dependent F-actin bundling, suggesting that D6 contains a cryptic F-actin binding site. NMR resonance assignments and 15N-relaxation measurements of D6-HP in 5 mM Ca2+ demonstrate that D6-HP consists of two independent structural domains (D6 and HP) connected by an unfolded 40-residue linker sequence. The headpiece domain in D6-HP retains its structure and interacts with D6 domain only through the linker sequencemore » without engaging in other interactions. Chemical shift values indicate essentially the same secondary structure elements for the D6 domain in D6-HP as in the highly homologous gelsolin domain 6. Thus, the headpiece domain of villin is structurally and functionally independent from the core domain.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
910265
Report Number(s):
PNNL-SA-55624
17990; KP1303000; TRN: US200723%%593
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Biochemistry, 46(25):7488-7496
Additional Journal Information:
Journal Volume: 46; Journal Issue: 25
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CALCIUM; CHEMICAL SHIFT; EPITHELIUM; PROTEINS; RESIDUES; RESONANCE; STABILITY; Environmental Molecular Sciences Laboratory

Citation Formats

Smirnov, Serge, Isern, Nancy G, Jiang, Zhenghui G, Hoyt, David W, and Mcknight, Christopher J. The Isolated Sixth Gelsolin Repeat and Headpiece Domain of Villin Bundle F-Actin in the Presence of Calcium and Are Linked by a 40-Residue Unstructured Sequence. United States: N. p., 2007. Web. doi:10.1021/bi700110v.
Smirnov, Serge, Isern, Nancy G, Jiang, Zhenghui G, Hoyt, David W, & Mcknight, Christopher J. The Isolated Sixth Gelsolin Repeat and Headpiece Domain of Villin Bundle F-Actin in the Presence of Calcium and Are Linked by a 40-Residue Unstructured Sequence. United States. https://doi.org/10.1021/bi700110v
Smirnov, Serge, Isern, Nancy G, Jiang, Zhenghui G, Hoyt, David W, and Mcknight, Christopher J. 2007. "The Isolated Sixth Gelsolin Repeat and Headpiece Domain of Villin Bundle F-Actin in the Presence of Calcium and Are Linked by a 40-Residue Unstructured Sequence". United States. https://doi.org/10.1021/bi700110v.
@article{osti_910265,
title = {The Isolated Sixth Gelsolin Repeat and Headpiece Domain of Villin Bundle F-Actin in the Presence of Calcium and Are Linked by a 40-Residue Unstructured Sequence},
author = {Smirnov, Serge and Isern, Nancy G and Jiang, Zhenghui G and Hoyt, David W and Mcknight, Christopher J},
abstractNote = {Villin is an F-actin regulating, modular protein with a gelsolin-like core and a distinct C-terminal 'headpiece’ domain. Localized in the microvilli of the absorptive epithelium, villin can bundle F-actin and, at higher calcium concentration, is capable of a gelsolin-like F-actin severing. The headpiece domain can, in isolation, bind F-actin and is crucial for F-actin bundling by villin. While the three-dimensional structure of the isolated headpiece is known, its conformation in the context of attachment to the villin core remains unexplored. Furthermore, the dynamics of the linkage of headpiece to the core has not been determined. To address these issues, we employ a 208 residue modular fragment of villin, D6-HP, which consists of the sixth gelsolin-like domain of villin (D6) and the headpiece (HP). We demonstrate that this protein fragment requires calcium for structural stability and, surprisingly, is capable of Ca2+-dependent F-actin bundling, suggesting that D6 contains a cryptic F-actin binding site. NMR resonance assignments and 15N-relaxation measurements of D6-HP in 5 mM Ca2+ demonstrate that D6-HP consists of two independent structural domains (D6 and HP) connected by an unfolded 40-residue linker sequence. The headpiece domain in D6-HP retains its structure and interacts with D6 domain only through the linker sequence without engaging in other interactions. Chemical shift values indicate essentially the same secondary structure elements for the D6 domain in D6-HP as in the highly homologous gelsolin domain 6. Thus, the headpiece domain of villin is structurally and functionally independent from the core domain.},
doi = {10.1021/bi700110v},
url = {https://www.osti.gov/biblio/910265}, journal = {Biochemistry, 46(25):7488-7496},
number = 25,
volume = 46,
place = {United States},
year = {Tue Jun 26 00:00:00 EDT 2007},
month = {Tue Jun 26 00:00:00 EDT 2007}
}